Attackers ambushed a Pakistani army convoy heading toward a counterterrorism sweep against Al Qaeda (searchmilitants near the Afghan border, killing at least 12 soldiers and wounding 15, officials said Tuesday.

The attackers fired rockets that hit at least six army trucks in the ambush near Sarwakai, about 30 miles east of Wana (search), the main town of the South Waziristan tribal region.

Some of the trucks were carrying fuel and were destroyed by fire in the attack Monday, a government official in Sarwakai said on condition of anonymity. He said 12 soldiers were killed and 15 were wounded.

Army spokesman Maj. Gen. Shaukat Sultan (searchconfirmed the attack and said army troops cordoned off the area to search for the assailants, but he declined to give more details.

Meanwhile, tribal leaders made little headway in a bid to end a week of fierce clashes near Wana between thousands of Pakistani troops and hundreds of Al Qaeda militants and sympathetic members of the Yargul Khel tribe.

Tribal elders were meeting with local officials in Wana on Tuesday to discuss their next step, after the Yargul Khel tribe had sought more time to discuss government demands, said Brig. Mahmood Shah, chief of security for the region.

Pakistani officials said Monday they discovered a mile-long tunnel leading from a besieged mud fortress that could have offered an escape route for top Al Qaeda suspects at the start of the operation.

President Gen. Pervez Musharraf said last Thursday that a "high-value" target was likely at the site. Some senior Pakistani officials have told The Associated Press that they believe Al Qaeda No. 2 Ayman al-Zawahiri (searchmay have been there, though the government has repeatedly said it does not know who is inside.

The Pakistani military imposed a 20-square-mile cordon to seal the area of the fighting, and say they are confident nobody has escaped.

But the cordon was not in place at the start of the operation on Mar. 16, when Pakistani forces who thought they were going to arrest local tribesmen were surprised by a ferocious barrage from within the compound walls. Fifteen soldiers and 26 militants died in the initial assault. The military sent in thousands of reinforcements over the following two days.

Pakistan's military said it was conducting DNA tests to identify six suspected foreign terrorists killed in the fighting, but would not elaborate on whether they included any important terror figures.

The military sweep in South Waziristan is the largest in Pakistan's tribal regions since the government threw its support behind the U.S.-led war on terrorism in late 2001. The operation has stirred anger in the tribal community, with local officials saying at least two dozen people including women and children were killed in army attacks on vehicles trying to flee the area at the weekend.

Brig. Mahmood Shah, chief of security for the tribal areas, said Monday that 123 suspects have been arrested in the week-old offensive. Security officials say the prisoners include Pakistanis, Arabs, Chechens, Uzbeks and ethnic Uighurs from China's predominantly Muslim Xinjiang province.

The peace delegation brought three government demands for the fighters: release 12 soldiers and two government officials taken captive last week; hand over tribesmen involved in the fighting; and kick out any foreigners or show the military where to track them down.

Shah had said he wasn't hopeful the delegation would succeed.

Meanwhile, assailants fired rockets in two attacks in the neighboring tribal region of North Waziristan, but caused no damage or injuries, an official said Tuesday.

Late Monday, two rockets landed on a hillside close to a paramilitary post in Isha, near the region's main town, Miran Shah, an official there said on condition of anonymity. Two more rockets landed near the village of Spin Wam, he said, but had no more details.